We plan to use our expertise in the diversity oriented synthesis of small molecule compounds for the preparation of 18-22 structurally unique pharmacophores. Many of the proposed strategies and synthetic approaches have already been optimized and published, thus increasing the probability of success. The proposed pharmacophores will be generated using solid and solution phase methods. The synthetic approaches to be pursued, while direct and productive, are highly practical and reproducible. The proposed compounds will significantly enhance the MLSMR collection. We will use different strategies for the diversity-oriented synthesis of a variety of unique heterocyclic compounds. Solid phase synthesis will be used to generate triazinediones, guanidino-ureas, aminotetrazoles, indolines, aminotriazoles, azoniaspiro, oxopiperazinium, and bis-cyclic compounds. We will use solution phase chemistry to produce novel indole, piperidine, tetrahydroquinoline, and steroid libraries. Additionally, we will develop synthetic approaches for the synthesis of unique organofluorinated compounds including DD-difluorocarbonyl compounds and varied difluoro-tetrahydropyrimidine derivatives. Fluorine-containing compounds have played a special role in medicinal chemistry and biomedical applications due to the unique influence of fluorine atoms on biological activity. In keeping with the themes of the investigator's research, we will target libraries of "Favored Pharmacophores" and employ the "Heteroatom Incorporation Strategy (HIS)" to generate novel libraries using diversity-oriented synthesis. The libraries are designed in a manner to balance size, diversity and complexity, and to optimize purity. This is essential to avoid false positives during the screening process. All proposed small molecule libraries are designed to follow known drug-likeness rules including 'Lipinski's Rule of Five'. All structurally unique libraries will consist of 100-200 individual compounds (10 to 20 mg of each) and will be prepared with purity equal or higher than 90% as required by the RFA. These will be transferred to the repository with detailed experimental protocols and solubility information. The libraries proposed were selected in a manner which does not overlap in chemical space with molecules currently in the PubChem database. The majority of the chemistries are well established in the Pi's and Co-Pi's laboratories. There has been and continues to be, a longstanding collaborative interaction between the Pis at Torrey Pines Institute for Molecular Studies and the Burnham Institute for Medical Research, which is part of the Molecular Library Screening Center Network (MLSCN). We thus have ready access to equipment and personnel at both organizations and to the MLSCN.